1. Field of the Invention
This invention relates to a method for ordering a disordered alloy and a method for making a perpendicular magnetic recording (PMR) medium, more particularly to a method involving simultaneously ion bombarding and annealing a disordered alloy for making a magnetic recording material of a PMR medium.
2. Description of the Related Art
As magnetic recording technology continues to advance, perpendicular magnetic recording (PMR) materials have been developed for achieving a need for a high density recording medium. It is known in the art that FePt alloy having an ordered phase (or L10 phase), i.e., a face-centered tetragonal (FCT) crystal structure, exhibits a high magnetocrystalline anisotropy energy (Ku) and thus can be used in a PMR medium to enhance the thermal stability of the PMR medium. In addition, the ordered FePt alloy has a coercive field (Hc) and a saturation magnetization (Ms) higher than the requirements of a satisfactory PMR medium, which are required to be at least 1.5 kOe and 100 emu/cm3, respectively. FePt alloy films for use in the PMR medium are usually formed by deposition techniques, such as sputtering techniques. The FePt alloy films thus formed normally have a disordered phase, i.e., a FCC (Face Centered Cubic) structure. Conventionally, the disordered FePt alloy can be annealed under a temperature of above 400° C. so as to be converted from the FCC structure into the FCT structure. However, the annealing temperature is too high and can result in damage to semiconductor components which the PMR material is integrated to.